At present, the application of power devices is becoming more and more widespread in fields of daily life, production, and so on. Especially, the power VDMOSFET has relatively fast switching speed, relatively small driving current, and relatively wide area of safe operation, thus it is appreciated by many researchers. Currently, power devices are developed to have increased operating voltage, increased operating current, reduced on-resistance and to become integrated. The contrivance of superjunction is an important milestone in the development of power VDMOSFET technology.
Power devices are not only popular in sophisticated technology fields of national defense, aerospace, aviation, etc., but are also appreciated in fields of industries, household appliances and so on. Along with the development of power devices, the reliability has become the main concern for people. Power devices provide required forms of electric power for electronic devices and provide driving energy for electrical machinery, they are applied in almost all electronic devices and electrical machinery, therefore, the study on reliability of power devices has great importance. Reliability is defined as the capability of a given device that will perform required functions under required conditions for a specific period of time. Required conditions typically refer to operating conditions and environment conditions; operating conditions refer to the conditions of stress that will have effects on the products or materials, such as electric stress, chemical stress and physics stress. As a consequence of the operating conditions, power devices are subjected to High power dissipation and intensive self-heating, so we should pay great attention to the reliability under high temperature and high pressure. High temperature reverse bias (HTRB) testis exactly a kind of test for evaluating the lifetime and reliability of power device chips under high temperature reverse bias. Under the specific conditions, the mobile ions (mainly are Sodium ions) introduced by package have certain chances to pass through the passivation layer and dielectric layer of the power device chips and enter the interface between silicon and silicon dioxide, and these mobile ions will change the electric field distribution on the silicon surface of the power device and degrade the withstand voltage of the power device. Therefore, it is of important significance to design a power device that can withstand HTRB test conditions.